Year	Percent
1969-01-01	1.692205342516890
1970-01-01	1.101280893643170
1971-01-01	0.872249481223546
1972-01-01	0.675387958145562
1973-01-01	0.669948647138653
1974-01-01	0.951948517972719
1975-01-01	1.399362419097270
1976-01-01	1.410020868459430
1977-01-01	1.245385858194250
1978-01-01	1.594002827780590
1979-01-01	1.486594324437080
1980-01-01	1.253026646961560
1981-01-01	1.845914355286240
1982-01-01	2.740075559808900
1983-01-01	3.485460243613650
1984-01-01	3.942206797795960
1985-01-01	3.618228862127670
1986-01-01	3.161507932422830
1987-01-01	3.607570326034920
1988-01-01	3.271843192936160
1989-01-01	2.826839998312310
1990-01-01	3.003671411839850
1991-01-01	3.351475131178820
1992-01-01	3.455360502800700
1993-01-01	4.031791726132570
1994-01-01	3.268539171264470
1995-01-01	3.216691828773410
1996-01-01	3.891013566105740
1997-01-01	3.938235530136560
1998-01-01	3.975018991704650
1999-01-01	3.649138975319800
2000-01-01	3.294462120100500
2001-01-01	3.425508683187150
2002-01-01	4.009115996565330
2003-01-01	4.341918088951310
2004-01-01	5.145496199907010
2005-01-01	5.437938969277480
2006-01-01	4.948682781443510
2007-01-01	4.489506083371250
2008-01-01	3.890318215317690
2009-01-01	5.484336800729440
2010-01-01	4.989801429248970
2011-01-01	4.550389969396230
2012-01-01	4.929702688697520
2013-01-01	5.373562246915200
2014-01-01	5.830175452407780
2015-01-01	6.087906084867540
2016-01-01	6.429439539128550
2017-01-01	5.914127447715240